Purifier



R. C. DARNELL Oct. 3, 1967 PURIFIER 2 Sheets-Sheet 1 Filed Aug. 19, 1965 INVENTOR. ,Fdf/fe? 7/ BY- p r PF/vJ/s. 1

R. C. DARNELL Oct. 3, 1967 PURIFIER 2 heets$heet 2 Filed Aug. 19, 1965 INVENTOR. %X' C, Zzrzre/Z United States Patent 3,344,927 PURIFIER Rex C. Darnell, Dexter, Mich., assignor to Michigan Dynamics, Inc., a corporation of Michigan Filed Aug. 19, 1965, Ser. No. 482,039 8 Claims. (Cl. 210360) ABSTRACT OF THE DISCLOSURE repository. To preclude re-entry of the particles into the fluid stream upon the cessation of rotation of the impeller, a perforatescreen is positioned adjacent the openings in the perforate member of the contaminant repository. This screen extends across the fluid inlet and outlet and is rotated when the impeller rotates to provide a self-cleaning action.

This invention relates to a purifier for extracting particles larger than a given size from a fluid and more particularly to a centrifugal purifier that removes particles of a given size from a fluid.

In my United States Patent No. 3,050,240, issued Aug. 21, 1962, entitled, Centrifugal Contaminant Extractor, and assigned to the assignee of this invention, the-re is illustrated a centrifugal purifier wherein contaminants are separated from a fluid by means of a centrifugal force. The fluid and entrained contaminants are centrifuged by a rotating impeller contained within an impeller cavity. The centrifugal force drives the contaminants into a contaminant repository that is positioned around the impeller cavity. An inner shell that defines the inner surface of the contaminant repository has specially formed louvers for permitting the contaminants to enter the repository and which aid in precluding the re-entry of the contaminants to the fluid system when the impeller is not rotating. In certain applications, however, it is desirable to provide a more positive means of assuring that the contaminants will not re-enter the fluid system.

-It is, therefore, an object of this invention to provide a centrifugal purifier for removing contaminants from a fluid that provides means for positively assuring that the separated contaminants will not re-enter the fluid.

-In certain types of fluid systems, it is necessary to insure that all particles in excess of a given size will be removed from the circulated fluid. The size of particles extracted by a centrifugal purifier of the type shown in my aforementioned patent depends upon such variables as the speed of rotation of the impeller, the diameters of the various components, the mass of the particles, the viscosity of the fluid and other factors. Since it is frequently difficult, if not impossible, to accurately control these factors and maintain them all constant, a centrifugal purifier of the type described in my aforementioned patent cannot be used in all applications wherein it is essential that particles in excess of a certain size are extracted from the fluid circulated. Although conventional depth or surface type of filters are capable of extracting particles in excess of a given size, these types of filters require frequent servicing which a centrifugal purifier does not require.

It is, therefore, a further object of this invention to provide a centrifugal purifier that is capable of extracting contaminants in excess of a predetermined size from a fluid.

It is a still further object of this invention to provide a self-cleaning type of filter that will extract particles in excess of a given size from a fluid.

A centrifugal purifier embodying this invention comprises a fluid cavity in which a rotating impeller is supported to impart a centrifugal force to the fluid and entrained contaminants in the cavity. A contaminant repository is provided in fluid communication with the cavity to receive the entrained contaminant-s that are driven from the cavity under the influence of centrifugal force. A fallout device having a plurality of finely spaced openings is positioned across the mouth of the contaminant repository to preclude re-entry of the contaminants to the fluid system upon the cessation of rotation of the impeller.

As a further feature of the invention, the fallout device may be in the form of an annular perforate member and the fluid is routed radially inwardly through the fallout device. The fallout device is rotated so that particles which are excluded from the circulated fluid by the fallout device will be thrown away from it by the centrifugal force of rotation.

Other objects and advantages of this invention will become more apparent as this description proceeds, particularly When considered in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a front elevational view of a centrifugal purifier embodying this invention;

FIGURE 2 is an enlarged partial cross-sectional view taken generally along the line 2-2 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2; and

FIGURE 4 is a perspective view of a portion of the centrifuge assembly shown in FIGURES 1 through 3.

Referring now in detail to the drawings, a centrifugal purifier embodying this invention is identified generally by the reference numeral 11. The centrifugal purifier 11 has many features in common with that disclosed in my aforementioned patent and reference may be had to that patent for specific details that are not disclosed herein because they form no part of this invention. The centrifugal purifier 11 includes an outer shell made up of a housing 12 and cover plate 13 that are aflixed together by a clamp assembly 14 that engages upstanding adjacent ribs 15 and 16 of the cover 13 and housing 12, respectively (FIGURE 2). An O-ring seal 17 is compressed between a chamfered annular shoulder 18 of the housing 12 and an annular groove 19 formed in the cover 13 to preclude fluid leakage from the purifier 11.

The cover 13 is provided with a flanged mounting portion 21 that is adapted to be aflixed to an engine or other prime mover. A drive shaft 22 is journaled within the cover 13 and has a splined end 23 that is adapted to be fixed in driving engagement with the prime mover. The internal supporting mechanism for the drive shaft 22 and seals which preclude leakage from the purifier 11 around the drive shaft 22 form no part of this invention and reference may be had to my aforementioned patent for details of the construction of these components. A fluid inlet fitting 24 and fluid outlet fitting 25 are formed in the cover 13 which communicate by means of suitable fluid passages with a hollow annular cavity 26 defined by the housing 12 and cover 13 and with the centrifuge assembly, indicated generally by the reference numeral 27, contained therein.

The centrifuge assembly 27 is comprised of a first generally cup-shaped housing 28 having a beveled outer end 29 that engages a similar beveled end 31 of a cover member 32. The cup-shaped housing 28 and cover member 32 define annular fluid cavity means in which entrained contaminants are centrifuged from a fluid as will become more apparent as this description proceeds.

A pilot shaft 35 has a male threaded end 36 that is threaded into a tapped hole 37 formed centrally in the housing 12. A hearing member 38 is positioned coaxially upon the pilot shaft 35 and a driving sleeve 39 is formed integrally with the housing 28 and journaled upon the bearing member 38. The drive sleeve 39 is splined or connected in any other suitable manner (not shown) to the drive shaft 22 so that the centrifuge assembly 27 will rotate with the drive shaft 22. The drive sleeve 39 has a male threaded end 41 that is received in a tapped hole 42 formed in a hub member. An O-ring seal 43 is compressed between the outer end of the hub member and the adjacent surface of the centrifuge cover member 32 to effect a fluid-tight seal in this area.

A generally cup-shaped inner shell 45 is affixed, by means of a plurality of screws 46, to the centrifuge assembly cover member 32. A perforate first inner shell 47 having louvered openings 48 is press fitted into an annular recess 49 formed at the inner periphery of the inner shell 45. The first perforate inner shell 47 and cup-shaped member 45 define a first annular contaminant repository 51 and the perforate inner shell 47 defines the outer periphery of a first annular fluid cavity 52. A plurality of impellers 53 are formed integrally with the hub portion of the cup-shaped member 28 and extend within the annular cavity 52 (FIGURE 3).

The cup-shaped housing 28 is affixed to the cover member 32 through the inner shell 45 by means of a plurality of screws 55 that are threaded through apertures in the base of the cup-shaped housing 28 and engage tapped holes 56 formed in the outer periphery of the inner shell 45. An annular gasket 57 is positioned between the adjacent surfaces of the inner shell 45 and cup-shaped housing 28 to insure against fluid leakage.

A second perforate inner shell 59 is press fitted onto an annular hub portion 61 of the centrifuge cover member 32 and defines a second fluid cavity 63 with the inner shell 45 and a second annular contaminant repository 64 with the cup-shaped housing 28. A plurality of louvered openings 65 are formed in the second inner shell 59 to permit fluid communication between the second cavity 63 and the second contaminant repository 64, for a purpose which will become more apparent as this description proceeds.

A fallout device for limiting the size of particles that may pass through the centrifugal purifier 11 and for precluding the re-entry of the separated contaminants into the fluid system when the impellers 53 are not rotating is positioned within the second annular fluid cavity 63. The fallout device comprises a generally conical shaped perforate shell 71 having an annular hub portion 72 that is press fitted onto an annular shoulder of the inner shell 45. A gasket 73 is positioned between the hub portion 72 and the inner shell 45. The conical shaped portion of the perforate shell 71 is provided with a plurality of apertures 74 that are of sufficient size and sufficiently closely spaced so as to not significantly restrict the flow through the shell 71.

Positioned radially inwardly of the shell 71 and supported by it is a conical screen 75 having a plurality of finely spaced, equally sized openings. The openings in the screen 75 are considerably smaller than the openings 74 and smaller than the openings provided by the louvers 65. The size of the openings in the screen 75 is selected to be the same as the smallest size of particle which may pass through the purifier assembly 11. Larger particles will thus be excluded from passage through the device, as will become more apparent as this description proceeds.

A plurality of circumferentially spaced by-pass openings 76 are formed in the shell 71 adjacent the hub portion 72. Similarily sized and spaced by-pass openings 77 are formed in the conical screen 75 adjacent the openings 76. The by-pass openings 76 and 77 serve a function that will become more apparent as this description proceeds.

Operation The purifier assembly 11 is adapted to be used in any type of fluid system, but is particularly useful in separating contaminants from the fuel of aircraft engines. In such a use it is adapted to be interposed in the fuel line and is supplied with fuel under pressure by a. fuel pump (not shown). Fuel enters the purifier assembly 11 through the inlet fitting 24 wherein it is directed 'by suitable passages (not shown) to the first annular cavity 52.

When the engine is operating, the drive shaft 22 is rotated and thus the centrifuge assembly 27 is also rotated due to its connection with the drive shaft 22, which has heretofore been described. The rotation, assisted by the action of the impellers 53 imparts a centrifugal force to the fluid and entrained contaminants. A portion of the contaminants will be driven into the first contaminant repository 51 through the louvered openings 48. The louvered openings 48 may be constructed in such a way so that they will assist in precluding escape of the contaiminants back into the fluid system, as is described in my aforementioned patent application, when rotation of the centrifuge assembly 27 ceases.

The fluid exits from the first annular cavity 52 through a plurality of radially extending fluid passages 81 that open into the rear of the second annular cavity 63 radially outwardly of the smaller diameter portion of the screen 75 (FIGURE 2). The centrifugal force will drive the entrained contaminants into the second contaminant repository 64 through the louvered opening 65. The louvered opening 65 also may be constructed to assist in precluding re-entry of the contaminants to the fluid system when rotation of the centrifuge assembly 27 ceases.

Any particles that are larger in size than the openings in the screen 75 and which have not previously been centrifuged from the fluid into one of the contaminant repositories 51 or 64, will not be free to pass radially through the screen 75 to fluid outlet openings 82 formed in the cup-shaped housing 28 due to the size of the openings in the screen 75. These larger particles will engage the outer periphery of the screen 75 and as it rotates with the remainder of the centrifuge assembly 27 the larger parti cles will eventually be centrifuged away from the screen 75 into the contaminant repository 64.

A very small percentage of the larger particles can pass through the centrifuge assembly through the by-pass openings 76 and 77. The quantity of such particles by-passing the screen 75 will be relatively small, however. If for some reason the screen 75 should become clogged due to an excess accumulation of particles, the flow of fluid to the engine will not be seriously restricted since by-pass flow can occur through the by-pass openings 76 and 77. If this bypass condition occurs, the centrifuge assembly should be disassembled and cleaned as soon as possible.

It should be noted that when rotation of the centrifuge assembly 27 and particularly the impellers 53 has ceased, particles might tend to escape from the contaminant repositories 51 and 64 into the fluid contained within the cavities 52 and 63. This escaping contaminant would be free to reenter the fluid system when the centrifugal purifier 11 were again caused to operate. The particles will, however, be precluded from re-entering the fluid system by the fallout screen 75. Immediately upon rotation of the screen 75 these particles will again be centrifuged back into the contaminant repository 64 and thus cannot pass from the centrifugal purifying assembly 11. If additional means for precluding the fallout of particles is desired, the contaminant repositories 51 and 64 may be filled with a foraminous entrapment media, as disclosed in the copending patent application of Richard L. Cannon, entitled Centrifugal Purifier, filed Oct. 23, 1965, Ser. No. 503,924 and assigned to the assignee of this invention.

The centrifugal action generated by the purifier 11 provides some boost in the pressure of the fluid circulated through the purifier assembly 11. If additional boost is desired, a boost-type purifier assembly, as shown in my Patent No. 3,178,105 issued Apr. 13, 1965, entitled Contaminant Extracting Boost Pump, and assigned to the assignee of this invention, may be utilized. The fallout screen 75 may be used in conjunction with a contaminant extracting boost pump of the type disclosed in that patent.

A plurality of circumferentially spaced separators 83 extend within the first contaminant repository 51 to preclude an unequal buildup of contaminant therein particularly when the centrifuge assembly 27 is at rest. Without the separators 83 the contaminant would collect at the lowest portion of the contaminant repository 51 and create an imbalance when rotation was again initiated; Similar separators 84 extends into the contaminant repository 64 to prevent an unequal buildup of contaminant in this repository.

Various other changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.

What is claimed is:

1. A centrifugal purifier for removing entrained contaminants larger than a predetermined size from a fluid in a fluid system comprising means defining a fluid cavity, fluid inlet means and fluid outlet means in communication with said fluid cavity, a rotating impeller supported within said cavity for imparting a centrifugal force to the fluid and entrained contaminants therein, a contaminant repository, said contaminant repository being defined at least in part by a member having enlarged openings for providing for fluid communication between said cavity and said contaminant repository for passage of entrained contaminants from said cavity to said contaminant repository under the influence of the centrifugal force generated by said impeller, and a perforate member having a plurality of finely spaced openings extending adjacent and across the openings in said first mentioned member and Within said cavity for precluding the re-entry of the contaminants to the fluid system upon the cessation of rotation of said impeller, said openings in said perforate member being sized to exclude particles greater than said predetermined size, said perforate member being positioned between said fluid inlet means and said fluid outlet means whereby at least a portion of the fluid flowing through said cavity passes through said perforate member.

2. A centrifugal purifier for separating contaminants having a size larger than a predetermined size from a fluid comprising housing means defining fluid cavity means, a rotating impeller for imparting a centrifugal force to the fluid and entrained contaminants in said cavity means, an annular perforate member supported for rotation within said cavity means, said perforate member having finely spaced openings sized to exclude particles greater than a predetermined size from fluid flowing through said perforate member, fluid inlet means opening into said cavity means radially outwardly of said perforate member, fluid outlet means opening into said cavity means radially inwardly of said perforate member whereby at least a portion of the fluid flowing from said fluid inlet means to said fluid outlet means passes radially inwardly through said perforate member, means for rotating said perforate member for driving the particles separated from the fluid by said perforate member away from said perforate member to prevent plugging thereof, and an annular contaminant repository encircling said perforate member, said contaminant repository being defined in part by an annular member having enlarged openings for fluid communication of said contaminant repository with said fluid cavity means for receiving and retaining the particles separated from the fluid by said impeller and by said perforate member, the openings in said annular member being substantially larger in area than the respective openings in said perforate member.

3. A centrifugal purifier for removing entrained contaminants from a fluid in a fluid system comprising means defining an annular fluid cavity, a rotating impeller supported within said cavity for imparting a centrifugal force to the fluid and entrained contaminants, an annular concontaminants from said cavity to said contaminant repository under the influence of the centrifugal force generated by said impeller, and an annular perforate member having a plurality of finely spaced openings positioned radially inwardly of said inner shell within said cavity for precluding re-entry of the separated contaminants to the fluid system upon the cessation of rotation of said impeller, the openings in said perforate member being substantially smaller than the openings in said perforate inner shell.

4. A centrifugal purifier for separating contaminants having a size larger than a predetermined size from a fluid comprising means defining an annular fluid cavity, a rotating impeller supported within said cavity for imparting a centrifugal force to the fluid and entrained contaminants, an annular contaminant repository surrounding said cavity and being defined in part by a perforate inner shell, the perforations in said inner shell providing for fluid communication between said cavity and said contaminant repository for passage of entrained contaminants from said cavity to said contaminant repository under the influence of the centrifugal force generated by said impeller, an annular perforate member supported for rotation within said cavity radially inwardly of said perforate inner shell, said perforate member having finely spaced openings sized to exclude particles greater than a predetermined size from fluid flowing through said perforate member,

fluid inlet means opening into said cavity radially outwardly of said perforate member,.fluid outlet means opening into said cavity radially inwardly of said perforate member whereby at least a portion of the fluid flowing from said fluid inlet means to said fluid outlet means passes radially inwardly through said perforate member, the openings in said perforate member being substantially smaller in size than the openings in said perforate inner shell, and

means for rotating saidperforate member for driving the particles separated from the fluid by said perforate member away from said perforate member into said contaminant repository to prevent plugging of said perforate member.

5. A centrifugal purifier for separating contaminants having a size larger than a predetermined size from a fluid comprising means defining an annular fluid cavity, a rotating impeller supported within said cavity for imparting a centrifugal force to the fluid and entrained contaminants, an annular contaminant repository surrounding said cavity and being defined in part by a perforate inner shell, the perforations in said inner shell providing for fluid communication between said cavity and said contaminant repository for passaeg of entrained contaminants from said cavity to said contaminant repository under the influence of the centrifugal force generated by said impeller, an annular perforate member supported for rotation within said cavity radially inwardly of said perforate inner shell, said perforate member having finely spaced openings sized to exclude particles greater than a predetermined size from fluid flowing through said perforate member, fluid inlet means opening into said cavity radially outwardly of said perforate member, fluid outlet means opening into said cavity radially inwardly of said perforate member whereby at least a portion of the fluid flowing from said fluid inlet means to said fluid outlet means passes radially inwardly through said perforate member, the openings in said perforate member being substantially smaller in size than the opening in said perforate inner shell, means for rotating said perforate member for driving the particles separated from the fluid by said perforate member away from said perforate member into said contaminant repository to prevent plugglng of said perforate member, and means affixing said impeller to said perforate member for simultaneous rotation of said impeller and said perforate member.

6. A centrifugal purifier for separating contaminants having a size larger than a predetermined size from a fluid comprising means defining an annular fluid cavity, a rotating impeller supported within said cavity for imparting a centrifugal force to the fluid and entrained contaminants, an annular contaminant repository surrounding said cavity and being defined in part by a perforate inner shell, the perforations in said inner shell providing for fluid communication between said cavity and said contaminant repository for passage of entrained contaminants from said cavity to said contaminant repository under the influence of the centrifugal force generated by said impeller, a conical perforate member supported for rotation within said cavity radially inwardly of said perforate inner shell, said conical perforate member having finely spaced openings sized to exclude particles greater than a predetermined size from fluid flowing through said perforate member, fluid inlet means opening into said cavity radially outwardly of said conical perforate member, fluid outlet means opening into said cavity radially inwardly of said conical perforate member whereby at least a portion of the fluid flowing from said fluid inlet means to said fluid outlet means passes radially inwardly through said perforate member, the openings in said perforate member being substantially smaller in size than the openings in said conical perforate inner shell, means for rotating said conical perforate member for driving the particles separated from the fluid by said conical perforate member away from said conical perforate member into said contaminant repository to prevent plugging of said conical perforate member, and means affixing said impeller to said conical perforate member for simultaneous rotation of said impeller and said conical perforate member.

7. A centrifugal purifier for removing entrained contaminants having a size larger than a predetermined size from a fluid comprising means defining fluid cavity means, a rotating impeller in said cavity means for imparting a centrifugal force to the fluid and entrained contaminants, an annular contaminant repository defined in part by a perforate inner shell extending around said cavity means,

the perforations in said inner shell providing for fluid communication between said cavity means and said contaminant repository for passage of entrained contaminants from said cavity means to said contaminant repository under the influence of the centrifugal force generated by said impeller, a conical perforate member having finely spaced openings sized to exclude particles greater than a predetermined size from fluid flowing through said perforate member, fluid inlet means opening into said cavity means radially outwardly of the smaller diameter portion of said conical perforate member, fluid outlet means opening into said cavity radially inwardly of the larger diameter portion of said conical perforate member whereby at least a portion of the fluid flowing from said fluid inlet means to said fluid outlet means passes in a substantially radially inward direction through said conical perforate member, and means for rotating said conical perforate member for driving the particles separated from the fluid by said conical perforate member outwardly from said perforate member into said contaminant repository to prevent plugging of said perforate member.

8. A centrifugal purifier as set forth in claim 2 wherein the means for rotating the perforate member includes means for affixing the impeller against rotation relative to said perforate member.

References Cited UNITED STATES PATENTS 1,202,723 10/1916 Jackson 210486 X 1,382,142 6/1921 Sturgeon 2332 2,750,107 6/1956 More 2332 2,874,897 2/1959 Corteggiani 2332 X 3,050,240 8/ 1962 Darnell 233-31 3,178,105 4/1965 Darnell 210 X 3,231,182 1/1966 Downey 233-2 3,233,737 2/1966 Hultgren 2l0434 FOREIGN PATENTS 659,294 3/ 1963 Canada. 757,526 10/ 1933 France.

REUBEN FRIEDMAN, Primary Examiner.

J. DE CESA'RE, Assistant Examiner. 

1. A CENTRIFUGAL PURIFIER FOR REMOVING ENTRAINED CONTAMINANTS LARGER THAN A PREDETERMINED SIZE FROM A FLUID IN A FLUID SYSTEM COMPRISING MEANS DEFINING A FLUID CAVITY, FLUID INLET MEANS AND FLUID OUTLET MEANS IN COMMUNICATION WITH SAID FLUID CAVITY, A ROTATING IMPELLER SUPPORTED WITHIN SAID CAVITY FOR IMPARTING A CENTRIFUGAL FORCE TO THE FLUID AND ENTRAINED CONTAMINANTS THEREIN, A CONTAMINANT REPOSITORY, SAID CONTAMINANT REPOSITORY BEING DEFINED AT LEAST IN PART BY A MEMBER HAVING ENLARGED OPENINGS FOR PROVIDING FOR FLUID COMMUNICATION BETWEEN SAID CAVITY AND SAID CONTAMINANT REPOSITORY FOR PASSAGE OF ENTRAINED CONTAMINANTS FROM SAID CAVITY TO SAID CONTAMINANT REPOSITORY UNDER THE INFLUENCE OF THE CENTRIFUGAL FORCE GENERATED BY SAID IM PELLER, AND A PERFORATE MEMBER HAVING A PLURALITY OF FINELY SPACED OPENINGS EXTENDING ADJACENT AND ACROSS THE OPENINGS IN SAID FIRST MENTIONED MEMBER AND WITHIN SAID CAVITY FOR PRECLUDING THE RE-ENTRY OF THE CONTAMINANTS TO THE FLUID SYSTEM UPON THE CESSATION OF ROTATION OF SAID IMPELLER, SAID OPENINGS IN SAID PERFORATE MEMBER BEING SIZED TO EXCLUDE PARTICLES GREATER THAN SAID PREDETERMINED SIZE, SAID PERFORATE MEMBER BEING POSITIONED BETWEEN SAID FLUID INLET MEANS AND SAID FLUID OUTLET MEANS WHEREBY AT LEAST A PORTION OF THE FLUID FLOWING THROUGH SAID CAVITY PASSES THROUGH SAID PERFORATE MEMBER. 